The flexibility of Khan Academy will be available to students and teachers in a new way this back-to-school season — and this particular classroom program is tailored toward rebuilding students' confidence as they work to overcome the infamous "summer slide."

The nonprofit education company is launching LearnStorm — a free, online learning challenge — to relieve some of the pressure on teachers as students get acclimated to the new school year. Signups opened Tuesday, and beginning Sept. 12, students in grades 3-12 will have six weeks to work with their classmates — or independently — to strengthen their skills in science, math, history and grammar.

The goal is to help students develop a growth mindset, Khan Academy says.

“It’s for every student, designed to celebrate progress, effort and teamwork,” said Mia Mellon, LearnStorm lead at Khan Academy. “It helps students build confidence, particularly with back-to-school [season], which can be a challenging time both for teachers and students.”

This is the first year LearnStorm will be available to the general public, but if the two years of trials are any indication, teachers and students participating in the challenge can expect positive results.

In a spring 2015 pilot, more than 70,000 students across 10 counties in the San Francisco Bay area used LearnStorm. In spring 2016, the same 10 counties used the learning program, plus the entire state of Idaho, the Chicago metro area, and all of Ireland — a total of 250,000 students.

Of those students, 96 percent said they felt their learning confidence increased, and of the 8,000 teachers involved in the 2016 pilot, 94 percent said they would recommend it to a colleague.

Kids at KIPP Heritage Academy in San Jose practice their skills on LearnStorm. (Khan Academy)

“We heard from teachers that this changes the way kids carry themselves in classrooms,” Mellon said, speaking particularly to the “growth mindset” aspect of LearnStorm. “It changed the way they look at struggling and making mistakes. … I think that’s why we’re so excited to bring this across the country and to see how it impacts [students].”

The six-week challenge, which runs through Oct. 20, allows students and classrooms a chance to earn digital prizes, like limited-edition badges on their Khan accounts, and real-life prizes, like stickers, pencils and other school supplies, Mellon said.

Ultimately, the program should serve as a “companion to help get the ball rolling” on a new school year, accommodating students at a variety of different levels.

Students at Mission Preparatory School in San Francisco earned certificates for their work in the LearnStorm pilot. (Khan Academy)

The program supports classroom-wide involvement, but it is also designed to make personalized learning easier. Teachers can browse the Khan Academy library and assign content to the entire class, to sub-groups within the class or to individual students. “It really lends itself to personalization,” Mellon said.

Classes are incentivized to work through the six levels of LearnStorm together, unlocking prizes along the way, but students and teachers can set a pace that’s comfortable and appropriate for them.

That’s one of the things that makes LearnStorm effective, the company says.

“It’s really important to us that it works in a variety of different classroom environments,” Mellon said. "Whether a school has limited access to devices — maybe each classroom only gets one hour a week in a computer lab or uses a rotating laptop/tablet cart — or if it’s a one-to-one district, LearnStorm is built to “be really flexible and work with the teacher where they see fit.”